iris: load application-owned fonts

app/Cargo.lock

@@ -180,6 +180,7 @@ dependencies = [
  "pulldown-cmark",
  "serde",
  "serde_json",
+ "swash",
  "tempfile",
  "tokio",
  "ureq",

app/Cargo.toml

@@ -56,6 +56,7 @@ force-gles = ["screens", "iris/force-gles"]
 [dev-dependencies]
 tempfile = "3"
 tokio = { version = "1.53.1", features = ["rt", "time"] }
+swash = "0.2.10"
 
 # APK builds select these profiles explicitly.
 [profile.android-release]

app/assets/fonts/NERD_FONTS_LICENSE.txt

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Ryan L McIntyre
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

app/build-icon-font.sh

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+# Rebuilds app/assets/fonts/nerd_icons.ttf.
+#
+# ai-app draws its icons as glyphs in a Nerd Fonts subset it ships, rather
+# than as ordinary Unicode out of whatever the platform resolved. Unicode's
+# own geometric shapes are what this replaced: `tool.rs` set its disclosure
+# mark with U+25B8/25BE/25B4, and once iris stopped bundling fonts
+# (2026-09-07) Iris's phone drew an empty box for them and this VM drew a
+# dot. UI_RULES: "don't rely on characters the platform might not have --
+# ship the glyph or the asset rather than hoping."
+#
+# The whole symbols font is 3 MB for the handful below, so what is
+# committed is a subset. Add a codepoint to GLYPHS *and* to
+# `app/src/ui/icon.rs` (the two lists have to agree -- a codepoint in
+# the Rust that this script did not subset is a glyph that silently isn't
+# there), then run this and commit the result.
+#
+# Needs python3 and network access; fontTools is fetched into a temporary
+# venv, so nothing has to be installed on the machine.
+#
+# The Mono face makes icon metrics stable; the Material Design family keeps
+# their meanings conventional.
+set -euo pipefail
+
+GLYPHS=(
+    U+F035D  # md-menu_down -- a card that is open
+    U+F035F  # md-menu_right -- a card that opens
+    U+F0360  # md-menu_up -- collapse this group again
+)
+
+url=https://github.com/ryanoasis/nerd-fonts/releases/latest/download/NerdFontsSymbolsOnly.zip
+here="$(cd "$(dirname "$0")" && pwd)"
+out="$here/assets/fonts/nerd_icons.ttf"
+work="$(mktemp -d)"
+trap 'rm -rf "$work"' EXIT
+
+echo "Fetching $url"
+curl -fsSL -o "$work/nf.zip" "$url"
+python3 -c 'import sys,zipfile; zipfile.ZipFile(sys.argv[1]).extractall(sys.argv[2])' "$work/nf.zip" "$work"
+
+python3 -m venv "$work/venv"
+"$work/venv/bin/pip" -q install fonttools
+
+unicodes="$(IFS=,; echo "${GLYPHS[*]}")"
+mkdir -p "$(dirname "$out")"
+# The Mono face, where every glyph is one em wide and one em tall, so two
+# icons at the same font size are the same size without either being given
+# one, which makes an icon's box predictable beside a line of text.
+"$work/venv/bin/pyftsubset" "$work/SymbolsNerdFontMono-Regular.ttf" \
+    --unicodes="$unicodes" \
+    --layout-features= \
+    --drop-tables+=DSIG \
+    --output-file="$out"
+cp "$work/LICENSE" "$here/assets/fonts/NERD_FONTS_LICENSE.txt"
+
+echo "Wrote $out ($(stat -c %s "$out") bytes) with ${#GLYPHS[@]} glyphs"

app/src/android/bench_client.rs

@@ -114,6 +114,7 @@ fn battery_line(samples: &[i32]) -> String {
 
 impl BenchClient {
     pub(super) fn new(mut ui_state: AndroidUiState, rsc: &mut StdRsc<Self>) -> Self {
+        crate::ui::register_fonts(&mut rsc.ui);
         let content = WidgetPtr::new().add(rsc);
         let loading = placeholder(rsc, "Loading fixture...");
         content(rsc).set(loading);
@@ -146,7 +147,7 @@ impl BenchClient {
         let font = rsc.ui.text.font_diagnostics();
         log::info!(
             "iris fonts: {} families found, default={:?} mono={:?}, resolved regular={:?} \
-             bold={:?} italic={:?} mono={:?}, icons={:?}",
+             bold={:?} italic={:?} mono={:?}",
             font.families_found,
             font.default_family,
             font.default_mono_family,
@@ -154,7 +155,6 @@ impl BenchClient {
             font.bold_resolved,
             font.italic_resolved,
             font.mono_resolved,
-            font.icon_family,
         );
 
         let mut client = Self {

app/src/android/transcript_client.rs

@@ -91,6 +91,7 @@ fn frame_report_controls(rsc: &mut StdRsc<TranscriptClient>) -> WeakWidget {
 
 impl TranscriptClient {
     pub(super) fn new(mut ui_state: AndroidUiState, rsc: &mut StdRsc<Self>) -> Self {
+        crate::ui::register_fonts(&mut rsc.ui);
         let content = WidgetPtr::new().add(rsc);
         let loading = placeholder(rsc, "Loading sessions...");
         content(rsc).set(loading);

app/src/desktop/app.rs

@@ -57,6 +57,7 @@ struct Client {
 
 impl DesktopAppState for Client {
     fn new(mut ui_state: DesktopUiState, rsc: &mut StdRsc<Self>) -> Self {
+        crate::ui::register_fonts(&mut rsc.ui);
         let (server, ca_pem) = super::startup::load_startup_config().unwrap_or_else(|e| {
             eprintln!("desktop-app: {e}");
             process::exit(2);

app/src/ui/icon.rs

@@ -0,0 +1,30 @@
+pub const OPEN: &str = "\u{F035D}";
+
+pub const CLOSED: &str = "\u{F035F}";
+
+pub const COLLAPSE: &str = "\u{F0360}";
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use swash::FontRef;
+
+    #[test]
+    fn every_icon_is_in_the_application_font() {
+        let font = FontRef::from_index(super::super::ICON_FONT, 0)
+            .expect("the application icon font parses");
+        let charmap = font.charmap();
+        for (name, glyph) in [("OPEN", OPEN), ("CLOSED", CLOSED), ("COLLAPSE", COLLAPSE)] {
+            let mut chars = glyph.chars();
+            let ch = chars.next().expect("an icon is one character");
+            assert!(chars.next().is_none(), "{name} is more than one character");
+            assert_ne!(
+                charmap.map(ch),
+                0,
+                "{name} (U+{:04X}) is not in nerd_icons.ttf -- add it to \
+                 build-icon-font.sh's GLYPHS and rerun the script",
+                ch as u32
+            );
+        }
+    }
+}

app/src/ui/mod.rs

@@ -2,6 +2,7 @@ pub mod composer;
 // Keep the 1.9 MB fixture out of ordinary APKs.
 #[cfg(feature = "fixture")]
 pub mod fixture;
+mod icon;
 pub mod markdown;
 pub mod row;
 pub(crate) mod tap;
@@ -13,6 +14,16 @@ use iris::prelude::*;
 use std::{mem, rc::Rc};
 use theme::Theme;
 
+const ICON_FONT: &[u8] = include_bytes!("../../assets/fonts/nerd_icons.ttf");
+
+pub(crate) fn register_fonts(ui: &mut Ui) {
+    if ui.is_font_registered(&Family::Icons) {
+        return;
+    }
+    ui.register_font(Family::Icons, ICON_FONT)
+        .expect("the ai-app icon font must register before text is drawn");
+}
+
 pub struct TranscriptScreen {
     /// The transcript's own `LazySpan` -- the layout *and* the scroll
     /// position, since a lazy span owns a `ScrollController` of its own
@@ -241,6 +252,7 @@ pub fn build_tree<Rsc: HasEvents>(
 where
     Rsc::State: FocusHost + OpenUrl,
 {
+    register_fonts(rsc.ui_mut());
     let theme = Rc::new(Theme::new(&mut rsc.ui_mut().paints));
     let list = LazySpan::new(Dir::DOWN, Pin::End).add(rsc);
     list.controller(

app/src/ui/tool.rs

@@ -1,6 +1,7 @@
 use crate::client::text_cap::{VERBATIM_BYTES, VERBATIM_LINES, cut, show_all_label};
 use crate::client::tool_summary::{ToolInput, parse_tool_input};
 use crate::client::transcript_fold::{ToolState, TranscriptItem};
+use crate::ui::icon;
 use crate::ui::markdown::highlight_into;
 use crate::ui::tap::{hold_edge, on_tap};
 use crate::ui::theme::Theme;